The present invention relates to a novel .alpha.-cyanoacrylate and an adhesive containing same.
.alpha.-Cyanoacrylates represented by the following general formula polymerize and cure rapidly in the presence of water adsorbed on the surface of a material to be bonded and afford an adhesive force of an extremely high strength, so are widely used as room temperature one-pack type instantaneous adhesives for the bonding of metals, plastics, rubber and wood: ##STR3##
As .alpha.-cyanoacrylates there are known those with R being alkyl, such as alkyl .alpha.-cyanoacrylates, e.g. methyl .alpha.-cyanoacrylate, ethyl .alpha.-cyanoacrylate, and isopropyl .alpha.-cyanoacrylate, those with R being an unsaturated group, such as alkenyl or alkynyl .alpha.-cyanoacrylates, e.g. allyl .alpha.-cyanoacrylate and propargyl .alpha.-cyanoacrylate, fluoroalkyl .alpha.-cyanoacrylates (Japanese Patent Publication No. 87404/1982), e.g. 2,2,2-trifluoroethyl .alpha.-cyanoacrylate and 2,2,3,3-tetrafluoropropyl .alpha.-cyanoacrylate, and alkoxyalkyl .alpha.-cyanoacrylates, e.g. 2-methoxyethyl .alpha.-cyanoacrylate and 2-ethoxyethyl .alpha.-cyanoacrylate.
Generally, in the case where an .alpha.-cyanoacrylate is used as an adhesive, the cyanoacrylate monomer which has been volatilized polymerizes in the presence of water contained in the air and adheres as a white powder to the surrounding portion of a bonded part (whitening phenomenon), thus impairing the appearance of the bonded material. When used in the assembly of electric and electronic parts, the volatilized monomer contaminates a contact portion and causes defective contact, or cures in a moving part, thereby causing malfunction. Besides, many of .alpha.-cyanoacrylates have a stimulative odor. Further, cured polymers thereof are hard and deficient in flexibility, so are inferior in heat- and water-resistance.
It is the object of the present invention to overcome the above-mentioned drawbacks of the prior art.